Tom Nolan: New pandemic flu guidelines – don’t forget your oximeter

New guidelines on the management of pandemic H1N1 influenza were published recently by the Department of Health. They include guidelines on when to refer patients to hospital (see below) and an update on the epidemiology of the disease: fewer than 1% of cases are admitted to hospital; 12-15% of patients admitted to hospital go on to need high dependency or critical care; and mortality for hospitalised adults is around 6%. The presence of co-morbidities among those admitted appears to vary with age and is very low in young children:

Patients with underlying co-morbidities fare worse. Very few hospitalised young children (<20%) have co-morbidities, but this rises to 40% in 5-14 year-olds. Asthma is the commonest co-morbidity in children and young adults. Almost all (90%) hospitalised adults >65 years of age have at least one co-morbidity.

These co-morbidities are associated with poor outcomes according to the guidelines:

The risk of both hospital admission and death are strongly influenced by co-morbidities. In hospitalised adults significant risk factors for fatal outcomes include COPD, diabetes, and heart disease. Obesity appears to be a risk factor for requirement for critical care but not for death.

Predictive factors for ICU and death as outlined in the guidelines include: dyspnoea, requirement for supplemental oxygen, pneumonia on admission, and tachycardia in adults.

Referral criteria in primary care
Back in primary care, the guidelines suggest that referral criteria for hospital care should include any of the following: signs of respiratory distress, oxygen saturation of 94% or less in air, dehydration, shock, any signs of sepsis, altered conscious level and seizures.
The guidelines state that all patients assessed in primary care should have their peripheral oxygen saturation measured by pulse oximetry.

Measurement of peripheral oxygen saturation by pulse oximetry is essential to exclude hypoxaemia. Absence of cyanosis does not exclude hypoxaemia.

Does this mean that all GPs should be asked – or told – to ensure that they carry an oximeter? Should the recommendation be revised as it’s impractical or should all GPs who don’t carry an oximeter fork out for one? They only cost around £40 after all.

Overall, the widely expected second wave of swine flu appears to be approaching at a slower rate than anticipated. Some parts of the media are even speculating, perhaps over-optimistically, that the second peak may have already occurred. Last week in England there was a small rise (8%) in the estimated number of cases according to the Health Protection Agency. In Wales the number of GP consultations for flu-like symptoms went down, possibly as a result of the half-term school holidays.

Tom Nolan is a trainee GP in London.

  • Pekka Valmari

    Pulse oximeters are helpful and can save lives.

    Cyanosis, one of the signs indicating a need for urgent medical attention in swine flu according to CDC, is all too difficult to detect by plain eyes. It may not become visible before the oxygen saturation is less than 80-85%, (even 60-80% in newborns)(1,2).

    On the other hand, mortality in childhood respiratory infections starts to increase already at levels (90-95%) (3), and even former Guidelines say hospitalisation should take place at SpO2 <93% in bronchiolitis (4). So this needs to happen without visible cyanosis!

    A GP once consulted me from a long distance by phone, asking if a small baby with very minor respiratory symptoms needed any further investigations. Having babies with RSV bronchiolitis on the ward at that time, I asked for her SpO2. It turned out to be 85-95%, so the infant was invited to paediatric hospital care. The first night after admission she became apnoeic with an SpO2 of 60%. Apnoeic spells can be the very first sign of bronchiolitis, especially in the youngest infants. In her case, specialist care was needed for over a week.

    We sure need pulse oximeters. The cost is negligible compared to increased diagnostic accuracy and avoidance of unfavourable outcomes – with eventual malpractice considerations. Furthermore, oximeters even help to discover undiagnosed cardiac problems in infants (5).

    As measuring SpO2 is a very simple and rapid procedure, I see no reason to keep trusting merely the (inexistent) doctor’s “Superman vision”.

    Ref. 1. West Med J 1992;156:392–8.
    2. Pediatrics 2009;124:823-36.
    3. Bull World Health Organ 2009;87:263–70.
    5. Arch Dis Child Fetal Neonatal Ed 2007;92:F219–24.

    Pekka Valmari, M.D., Consultant paediatrician
    Lapland Central Hospital, Rovaniemi, Finland

  • David Tweedie

    I’m retired, but seriously consider buying one to assess the need to persuade my relatives – and myself – to seek help.
    I remember the days before pulse oximetry. I think it is one of the great advances in medicine in the last 50 years. It does need some knowledge to interpret, particularly when the individual is poorly perfused, but the device fails safe, which is more than can be said for other more expensive tools.
    At £40 it is a snip, particularly given the size. Modern ones are the size of the finger probe of earlier ones!
    David Tweedie [retired consultant anesthetist]

  • I recently purchased an oximeter for my seven year old child. He carries it around in his pocket at the playground at all times and I know it is definitely a life saver. It has accurate readings, portable and fits in your pocket.